1. Field
The disclosed embodiments relate to techniques for driving displays from computer systems. More specifically, the disclosed embodiments relate to techniques for providing multiple hardware paths for controlling a backlight of a display in a computer system.
2. Related Art
Interactions between a user and a computer system may be facilitated by a display of the computer system. For example, a liquid crystal display (LCD) panel of a laptop computer may allow the user of the laptop computer to view graphical user interfaces (GUIs) for an operating system and/or one or more applications executing on the laptop computer. One or more attributes of the display may also be dynamically adjusted and/or configured during use of the computer system. For example, the operating system may adjust the brightness of the display by transmitting commands that modify the duty cycle and/or frequency associated with pulse-width modulation (PWM) of power to the display's backlight.
On the other hand, native support for backlight control in the computer system may not be compatible with all operating systems on the computer system. For example, the computer system may be a multi-boot computer system with hardware that supports backlight control through a graphics-processing unit (GPU) of the computer system. As a result, a first operating system that is compatible with the hardware may issue backlight control commands to the GPU, while a second operating system that uses Advanced Configuration and Power Interface (ACPI) for backlight control may be unable to interface with the GPU to control the backlight.
In addition, conventional mechanisms for enabling backlight control for operating systems that are not natively supported by backlight control hardware may be intrusive and/or associated with significant overhead. Continuing with the above example, an ACPI command for backlight control from the second operating system may be trapped before the command is translated into a GPU-compatible command that is then is transmitted to the GPU. Such trapping of the command may cause the operating system to freeze, resulting in noticeable performance degradation during processing of long sequences of backlight control commands from the operating system and/or the delayed processing of some backlight control commands from the sequences.
Hence, what is needed is a mechanism for reducing overhead associated with providing backlight control to operating systems that are unable to use natively supported backlight control mechanisms in computer systems.